1. Field of the Invention (Technical Field)
The present invention relates to the lifting, moving, maneuvering, and positioning of large heavy objects, particularly trench covers or utility access plates.
2. Background Art
Note that the following discussion refers to a number of publications by author(s) and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-a-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
Large, unwieldy objects often require lifting and positioning, such as utility access plates and trench covers. Prior art devices, specifically for use with trench covers, have offered some assistance, but fall short in design, requiring trench covers with specially designed orifices for insertion of the device. (See U.S. Pat. No. 4,488,706 to Kono, U.S. Pat. No. 4,662,607 to Monchizuki et al., U.S. Pat. No. 6,202,985 to Chong et al., and U.S. Pat. No. 4,978,103 to Moisan.) Other devices require that a hook receipt area be formed on the trench cover or other object to be moved. (See U.S. Pat. No. 5,382,131 to Werthmann and U.S. Pat. No. 4,365,925 to Girtz.) With the different device, trench cover, and other utility access panel manufacturers, it would prove difficult to find one device which would easily access all panels and covers. Further, these access cover-specific devices could not be used on other heavy metal objects since they would not necessarily have an insertion point for receipt of hooks or shape specific “keys.” Therefore, there is a great need for an apparatus which can be easily used on all access covers as well as other heavy metal objects.
Another problem with the prior art devices heretofore mentioned is that they all have fixed axle lengths. For larger access panels with sizable width and lengths, the prior art devices could not straddle the resultant large opening. This would render the devices useless or at least a safety hazard since they would or might fall in the resultant hole. This is an unacceptable risk to a user. For these and other reasons, there is a great need in the art for an apparatus for lifting heavy objects which has an adjustable axle width for accommodating larger openings.